Placental maturity of grade 2 or higher, along with a gestational week of 37 weeks or more, is sufficient for delivery. A placental maturity level of 2 marks the maturity of the placenta; a gestational week of 37 weeks or more indicates full term. There are four levels of placental maturity: level 0, level 1, level 2 and level 3. level 1 marks basic maturity of the placenta; level 2 marks maturity of the placenta; level 3 marks senescence of the placenta. Due to calcification and fibrin deposition, the placenta’s ability to transport oxygen and nutrients is reduced, and the fetus will be at risk of oxygen deprivation at any time. Usually in the middle of pregnancy (13-28 weeks) placental maturity is grade 0; in the late pregnancy (30-32 weeks) placental maturity is grade 1; after 36 weeks placental maturity is grade 2. Usually at 38 weeks of pregnancy, the placenta can enter level 3. If placenta maturity level 3 is found before 37 weeks of pregnancy, premature placenta should be considered and the possibility of intrauterine fetal growth retardation needs to be alerted.